Incremental Threat Modeling

DevSecOps' rapid change velocity makes comprehensive threat modeling for every change impractical. Incremental threat modeling focuses analysis on what's changing rather than repeatedly analyzing entire systems. This approach maintains security visibility while matching development pace.

Change-based threat analysis examines modifications to identify new or altered threats. Adding a new API endpoint triggers analysis of authentication, authorization, input validation, and data exposure threats specific to that endpoint. Modifying database queries prompts injection threat review. Infrastructure changes trigger architectural threat analysis. This focused approach provides relevant insights without analysis paralysis.

Threat model inheritance enables new components to build on existing analysis. Microservices sharing common frameworks inherit baseline threats and mitigations. New features extending existing functionality inherit and extend threat models. This inheritance reduces redundant analysis while ensuring comprehensive coverage. Version control for threat models enables tracking inheritance relationships.

Delta threat modeling compares before and after states to identify security implications of changes. This might reveal that refactoring inadvertently removed security controls or that new features create unexpected attack paths. Automated comparison tools highlight security-relevant differences, focusing human review on significant changes rather than requiring complete re-analysis.